Generate random keystone users

Depends-On: https://gerrit.mcp.mirantis.com/#/c/44319/
Depends-On: https://gerrit.mcp.mirantis.com/#/c/45118/
Depends-On: https://gerrit.mcp.mirantis.com/#/c/45119/

Related-Prod: PROD-29868
Related-Prod: PROD-31315
(cherry picked from commit f5956c2f6151cc5d99659103f90641ea66eac44a)
(cherry picked from commit 70dd0f0587eb297fbefdea43837839c4983b8378)

Change-Id: I402be73437d5397224184a4fd71e2f6abae24db2
diff --git a/keystone/client/service/octavia.yml b/keystone/client/service/octavia.yml
index c5ca83f..b6dab99 100644
--- a/keystone/client/service/octavia.yml
+++ b/keystone/client/service/octavia.yml
@@ -15,6 +15,7 @@
             service:
               user:
                 octavia:
+                  name: ${_param:keystone_octavia_username}
                   is_admin: true
                   password: ${_param:keystone_octavia_password}
                   email: ${_param:admin_email}
@@ -39,7 +40,7 @@
                 admin_path: '/'
         octavia_identity:
           admin:
-            user: octavia
+            user: ${_param:keystone_octavia_username}
             password: ${_param:keystone_octavia_password}
             project: service
             host: ${_param:keystone_service_host}